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61.
Katritzky AR Khashab NM Kirichenko N Singh A 《The Journal of organic chemistry》2006,71(24):9051-9056
In an operationally straightforward and efficient method, amidrazones and amidoximes are prepared in yields of 65-87% from imidoylbenzotriazoles by microwave heating for 5-20 min with the appropriate hydrazine or hydroxylamine. 相似文献
62.
A theoretical model of the EOF and hydrodynamic flow in wide closed cylindrical capillaries, after the application of a stepwise voltage, is developed. Analytical expressions have been obtained as a sum of the solutions for the direct flow and backflow in both periodical and aperiodical regimes with arbitrary pulse/pulse or pulse/pause durations and amplitudes. The numerical analysis, performed for a few types of periodical and aperiodical regimes, shows the qualitative peculiarities of the liquid velocity profiles and its displacement for different numbers of pulses. The obtained results are compared with those obtained in the case of open capillaries. The possibility of the application of aperiodical stepwise regime for the investigation of electrophoresis is discussed. 相似文献
63.
Volodymyr Samaryk Sergiy Varvarenko Ihor Tarnavchyk Nataliya Nosova Nataliia Puzko Stanislav Voronov 《Macromolecular Symposia》2008,267(1):113-117
A principal possibility of the utilization of polymer peroxides for the modification of polymer surfaces that provides an immobilization of the tailored quantity of peroxide groups at them has been established. The processes of polymer surface activation with following “grafting from” or “grafting to” utilizing immobilized peroxide groups has been studied using a FTIR-ATR spectroscopy, ellipsometry and measurements of contact angles. The proposed technique of polymer surface activation is based on the universal ability of carbon chain polymer to participate the free radical reactions. 相似文献
64.
Nina N. Chipanina Nataliya F. Lazareva Tamara N. Aksamentova Evgeniya P. Doronina Bagrat A. Shainyan 《Journal of Physical Organic Chemistry》2014,27(11):892-901
The intramolecular С=O→Si coordination in H‐complexes of (acetoxymethyl)trifluorosilane and (benzoyloxymethyl)trifluorosilane with proton donors HCl, PhOH, MeOH, and CHCl3 was investigated by density functional theory and second‐order Møller‐Plesset perturbation theory (MP2) methods. Interrelation and mutual influence of the intramolecular coordination bond С=O→Si and intermolecular hydrogen bonds C=O···H and Si–F···H in H‐complexes was established using the AIM and NBO analyses. The С=O→Si coordination is weakened by the C=O···H hydrogen bonding but enhanced by the Si–Fax···H hydrogen bonding. The structure of H‐complexes of (acetoxymethyl)trifluorosilane with proton donors in solution was determined by comparing the ν(C=O) and ν(Si–F) frequencies calculated using the conductor‐like polarizable continuum model and their experimental Fourier transform infrared values. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
65.
Jan C. Schmidt Alvydas Lisauskas Hartmut G. Roskos Nataliya V. Demarina 《Superlattices and Microstructures》2012
Field-pinning layers are an approach to improve the homogeneity of the electric field in a biased semiconductor structure of length above the Kroemer criterion. Building a THz Bloch oscillator with such a structure requires superlattice regions. Nevertheless, GaAs layers are investigated here. We compare different periodic structures (alternating transit and field-pinning layers) via simulating the field distribution. It is shown that the development of propagating Gunn domains is suppressed when field-pinning layers are included, but the homogeneity of the field is still not satisfying for the purpose of building a Bloch gain THz source. Depending on the temperature, intra- and inter-period inhomogeneities occur. 相似文献
66.
N. A. Shurygina A. M. Glezer I. E. Permyakova E. N. Blinova 《Bulletin of the Russian Academy of Sciences: Physics》2012,76(1):44-50
The kinetics of primary crystallization and the effect of structural parameters of the precipitating nanocrystalline α-phase
Fe-Si on changes in microhardness, coercive force, and saturation magnetization in an amorphous Finemet-type 5BDSR alloy (Fe78.5Si13.5B9Nb3Cu1) obtained by melt quenching are studied. It is found that both an increase in bulk density and an increase in the average
nanoparticle size contribute to the hardening of the amorphous/nanocrystalline alloy. 相似文献
67.
Elena A. Reshetnyak Nataliia V. Ivchenko Nataliya A. Nikitina 《Central European Journal of Chemistry》2012,10(5):1617-1623
Photometric determination of aqueous Co(II), Cu(II), Ni(II) and Fe(III) was performed using indicator films prepared by immobilization
of 1-nitroso-2-naphthol-3,6-disulfonic acid disodium salt (NRS) into hardened photographic film. Immobilization was based
on electrostatic interaction of reagent and metal complexes with the gelatin. The isoelectric point pH of hardened gelatin
(4.46±0.04) was evaluated by viscometry. Co(II), Fe(III), Ni(II) form 1:3 complexes with NRS in gelatin at pH 2 and Cu(II)
forms 1:2 complexes. Their log β′ values were: Co-6.7, Fe-8.6, Cu-8.0, and Ni-6.4. The absorption maxima were: 370nm for NRS,
and 430nm, 470nm, 495nm and 720nm for complexes of Co(II), Ni(II), Cu(II) and Fe(III). An algorithm for their simultaneous
determination using the indicator films was developed. The detection limits were: clim(Co2+) = 0.45×10−5 M, clim(Fe3+) = 0.50×10−5 M, clim(Cu2+) = 0.67×10−5 M, clim(Ni2+) = 0.75×10−5 M,; and their sum clim(ΣMn+) = 0.82×10−5 M.
相似文献
68.
Maksimchuk NV Kovalenko KA Fedin VP Kholdeeva OA 《Chemical communications (Cambridge, England)》2012,48(54):6812-6814
Mesoporous metal-organic frameworks Cr- and Fe-MIL-101 are highly efficient, true heterogeneous and recyclable catalysts for solvent-free selective oxidation of cyclohexane with molecular oxygen and/or tert-butyl hydroperoxide under mild conditions. 相似文献
69.
Vakhid A. Mamedov Nataliya A. Zhukova Alsu A. Balandina Sergey V. Kharlamov Tat'yana N. Beschastnova Il'dar Kh. Rizvanov Shamil K. Latypov 《Tetrahedron》2012,68(36):7363-7373
An efficient and versatile one-step method for the synthesis of thiazolo[3,4-a]quinoxalines and related new heterocyclic systems have been developed on the basis of a new strategy for the construction of the pyrazine ring system. The key step of the process involves the cascade annulation of the iminothiazolopyrazine system to benzene in the reaction of 4-hydroxy-3,5-diaryl-2-phenyliminothiazolidines with 1,2-diaminobenzenes. The use of selenium analogues instead of thiazolidine derivatives in this reaction, leads to selenazolo[3,4-a]quinoxalines and the use of aza analogues instead of 1,2-diaminobenzenes gives aza analogues of thiazolo[3,4-a]quinoxalines. 相似文献
70.
Boris A. Trofimov Alexander V. Artem’ev Svetlana F. Malysheva Nina K. Gusarova Nataliya A. Belogorlova Anastasiya O. Korocheva Yuriy V. Gatilov Victor I. Mamatyuk 《Tetrahedron letters》2012,53(19):2424-2427
2-Bromopyridine reacts with elemental phosphorus (red or white) in a superbasic KOH/DMSO(H2O) suspension at 100 °C (for red phosphorus) and 75 °C (for white phosphorus) over 3 h to afford tris(2-pyridyl)phosphine in a 62% yield (from red phosphorus) and a 50% yield (from white phosphorus). Under microwave assistance, the reaction with red phosphorus takes just 20 min to produce tris(2-pyridyl)phosphine in 53% yield. A hitherto unknown complex, [Pd(PPy3)2Cl2]·CH2Cl2, synthesized from tris(2-pyridyl)phosphine and PdCl2, has the cis-configuration; this is unusual for bis(phosphino)palladium dichloride complexes. 相似文献